The use of control means including electromagnetic clutch means for selectively coupling gear driven work members or shafts is generally known. Also known are variable speed gear arrangements for selectively driving work members at two different speeds. Normally, however, these gear arrangements require shifting of the gears for changing from one speed to another and the electromagnetic clutch means serves merely to transfer the power from one gear train to another.
In those instances where a substantial difference in speed or RPM is required between the drive means and the work member, for example, conversion ratios on the order of 1:50, 1:100, or even 1:30, the known gear arrangements are not only costly to produce but are also relatively noisy in operation. Additionally, such devices require substantial space requirements to permit shifting the gear trains to the proper positions to obtain the selected gear conversion for operating the work member at the desired speed.